The US food company has until 5pm to formalise its offer for the British confectioner or walk away under the “put up or shut up” rules set by the UK Takeover Panel.
According to weekend reports, Kraft will press ahead with its offer and make a hostile bid directly to Cadbury shareholders ahead of the deadline.
Cadbury rejected the US firm’s £10.2bn offer, about 745 pence per share, in September.
Reports suggest that Kraft is unlikely to go much higher, if at all than the original offer.
Cadbury chiefs are understood to have been encouraged by Kraft’s third quarter results, which saw the Dairylea and Capri-Sun maker report a 5.7% drop in sales for the three months to the end of September.
Kraft also owns the Kenco, Oreo, Jacobs and Toblerone brands while Cadbury makes Trident chewing gum, Green & Black’s and Caramel bars.